Hooks for coupling onto bolts or pins attached to a piece of farming equipment comprise, in general, a semi-circular concave jaw-like member arranged to receive the bolt. Suchcoupling hooks where the bolt extends through a jaw in the hook are in common use today.
These coupling mechanisms presently in use leave much to be desired. To release the coupling bolt, the hook must be pulled off the bolt in the tangential direction. Such tangential movement involves a certain amount of friction between the coupling bolt and the cooperating end of the locking bolt of the coupling hook. This friction can be very damaging, especially in agricultural operations because of the considerable amount of dirt and grit present which causes abrasive wear on the contacting parts. Due to such abrasive wear the coupling bolt will start to rattle in the coupling hook and the hook will begin to whip.
Furthermore, the cylindrical seating area for the coupling bolt in the opening or jaw of the coupling hook is very vulnerable because the access of dirt into this region cannot be prevented in farming operations.